Effect of inflammation on positive margins of basal cell carcinomas

The use of preparations such as imiquimod in the treatment of basal cell carcinoma is well accepted. Imiquimod induces interferon-alpha, other cytokines, antigen-presenting cells and innate immunity, against tumour cells. The current study investigated whether the inflammation induced from a surgical procedure could have a similar effect on removing residual tumour after an excision.

A retrospective audit was carried out on basal cell carcinoma removed in the Dermatology Clinic of the Royal Newcastle Centre in 2007. The end-point focussed on the features of those tumours which initially had a positive margin, but were found to have no remaining tumour on subsequent excision.

A linear regression was carried out, revealing two significant predictors of outcome. These were the location of the basal cell carcinoma excision and the excision type. Punch biopsies and excisional biopsy had a greater number of histopathologically negative wider excisions despite initial positive margins. Facial lesions had a greater number of negative wider excisions.

The study has shown the majority of negative re-excisions were from lesions on the head which had had an initial surgical procedure. However, the evidence is not strong enough to advocate a protocol for dealing with positive margins. A larger sample size that encompassed all three factors that affect outcome, that is, the location of lesion, type of lesion and type of excision carried out, would be required in order to make a more definitive statement on protocol change for treatment of basal cell carcinoma.